Gas turbine power plant



Feb. 17, 1953 J. A. RYDMARK `ET AL 2,628,755

' GAS TURBINE POWER PLANT Filed Nov. 26, 1948 Josef A. Rydmdrk Haakon 0.Pldcrsan am P; 0am

Y ATTORNEY Patented Feb. 17, 1953 y GAS TURBINE POWER PLANT Josef A.Rydmark, Lansdowne, and Haakon O. Pedersen, Philadelphia, Pa.,assignors, by mesne assignments, to the United States of America asrepresented by the Secretary of the Navy Application November 26, 1948,Serial No. 61,973

6 Elaims.

This invention relates to elastic fluid machines, such as gas turbinepower plants, and has for an object the provision of improved apparatusof the class described.

It is a more specific object of the invention to provide an improvedaviation gas turbine power plant having novel features of constructionpar ticularly useful in apparatus of large size and high thrust rating,and permitting the maintenance of the over-all length of the plantwithin desirable limits. It is also an object to provide an improvedconstruction and arrangement or elements facilitating the manufacture,assembly and repair of gas turbine apparatus of this type.

Another object of the invention is the provision of an improved gasturbine power plant having a spindle aggregate including a compressorrotor, shaft and turbine rotor supported on a pair of bearings in such amanner as to minimize deflection of the spindle aggregate when subjectedto gyroscopic and gravitational loading.

A further object of the invention is the provision of a power planthaving a spindle aggregate constructed and arranged to resist deflectionto a degree permitting the eiiicient use of small clearance between therotating and stationary parts, favoring economical operation of theapparatus.

An important feature of the invention is the provision of a rotoraggregate supported on a pair of bearings and comprising a plurality ofdiscs or annular members bolted in coaxial relation by means of a numberof longitudinally arranged .-studs, the discs adjacent one end havingopenings forming a chamber which is adapted to receive one of thebearings, so that the span of the rotor aggregate between the twobearings will be less than its total length for minimizing deflec- *tionunder gyroscopic and gravitational loading.

t These and other objects are effected by the invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawing, forming a part of athis application, inwhich: I

Fig. 11 is a diagrammatic elevational View, partly vin section, of animproved gas turbine power plant having a rotor constructed inaccordance with the invention; and

Fig. 2 is a fragmentary sectional view, in enn larged detail, of aportion of the rotor of the compressor shown in Fig. l..

The present invention may be employed in the constructionofjeither aturbojet or a turboprop engine, the. apparatus illustrated in Fig. 1being of the turbojet type andy comprising a cylindrical outer casingstructure IIl having mounted there- 1n a sectional core structure I2 fordefining an annular fluid flow passageway I3, which extends axiallythrough the power plant from an annular air inlet opening I4tofarearwardly disposed dis charge nozzle I5. 'I 'he elements of thepower` plant are arranged in alignment with the axis thereof, thusminimizing the frontal area and drag incident to forward motion of theaircraft (not shown) which will carry the turbojet with the inletopening .pointed ,in the direction of night. The main elements l of theengine include a cowl or fair-ing I'i, housing auxiliary control andstarting equipment (not shown), an axial-flow compressor i8 having arotor assembly I9, annular combustionr apparatus ,26, and a turbine 2Ihaving a Arotor assembly 22 which is operatively connected to thecompressor rotor through the medium of a tubular shaft 23 disposedinteriorly of the combustion apparatus. Associated with the combustionapparatus 20 are a plurality of annular fuel manifolds and nozzles 24,which aresupported on suitable radial struts (not shown) through whichthe u sual fuel supply lines are adapted to extend.

According to the invention, as hereinafter more fully described, thecompressor rotor assembly I9, shaft 23 and turbine rotor assembly 22constitute a spindleaggregate that is journaled on twob'earings,consisting of a forwardly disposed thrustbearing 21 suppOrted bymeans ofa load carrying structure and struts 2B disposed in advance of thecompressor, and a rear bearing 3D supported by radial struts 3I whichare disposed downstream with respect to the turbine 2 l.

The general principles of operation of such a gas turbine power plantare well known. Air entering the air inlet opening I 4 is compressed bythe Ycompressor I8 andL conducted through the annular passage'I`3 to thecombustion apparatus 2t, where fuel supplied by way of nozzles 24 isburned to create the necessary motive fluid, which is expanded throughthe turbine 2I and nally discharged by way of the nozzle I5, forestablishing a propulsive thrust. p v

According to the invention, the rotor assembly i9 of the compressor I3comprises a plurality of discs, designated by the reference `characters35j to 45,- inclusive, which may constitute successive stages of thecompressor. Each of the discs is provided with a plurality of radially`disposed blades, designated generally by thereference character 4S.Arranged in cooperative relation with the rotaryblades carried by theturbine rotor I9 arev a plurality of annular'diaphragms carrying radialstationary blades, such as those indicated by the reference character 41in Fig. 2, it being understood that any suitable means for mounting thediaphragms in the casing structure II may be provided.

The discs of the compressor ro-tor I9 are assembled in coaxial relation,each of the sides of cach disc having formed thereon a concentricannular clutch portion a on which radially disposed teeth are formed,the clutch portions a of adjacent discs being thus adapted to beinterlocked together, as shown in Fig. 2. The annular clutch portions aand the teeth formed thereon are elevated or projected from the sidefaces of the respective compressor discs, so that the main portions ofadjacent faces of the discs are separated from each other inwardly andoutwardly of the engaging clutch portions. In the form of the apparatusillustrated in the drawing, the rearwardly disposed compressor discsincluding the discs 38 to 45 havev solid central portions, while theforwardly disposed discs or annular members 35, 36 and 31 are providedwith somewhat enlarged inner web portions surrounding central apertures35a, 36a and 31a, respectively. For supporting the compressor rotor I9on the frontal thrust bearing assembly 21, as hereinafter more fullyexplained, the disc or annular members 31 is secured to a suitablyflanged journal member 48 by means of bolts 49 (see Fig. 2).

The interlocking compressor discs are held in assembled relation bymeans of a plurality of longitudinally disposed stay rods or studs 50which are mounted in suitable registering bores formed in the respectivediscs, the bores being angularly spaced about and equidistant from theaxis of the rotor assembly.

The tubular shaft 23, as shown in Fig. 1, has a diameter suiiicient towithstand bending stresses imposed on the spindle aggregate duringrotation, and in the present embodiment of the invention is of adiameter substantially equal to .that of the annulus of the interlockedteeth of the clutch portions a on the compressor discs. The tubularshaft 23 may be formed by joining a plurality of cylindrical sectionshaving annular flanges that are secured together by bolts or othersuitable means (not shown). A forwardly disposed flange 51 of the shaft23 is secured to a bolting face of an annular member on the end disc 45of the compressor rotor structure. A rearwardly disposed annular flange61 is likewise provided for securing the shaft 2&3 to the end of afrusto-conical drum 68, which has an annular flange suitably bolted bybolts 69 to the rotor 22 of the turbine 2|.

According to the invention, the forwardly disposed discs of thecompressor rotor have formed therein central apertures, which, with thediscs assembled together, constitute an axially disposed chamber withinthe rotor of sufficient size to receive `the thrust bearing 21, so thatthe span of the spindle aggregate between the two supporting bearings issubstantially less than the over-all spindle length.

Referring to Fig. 2, in the preferred form of compressor rotor structureillustrated, the discs or annular members 35, 36 and 31 having the respective apertures 35a, 36a and 31a, are adapted to form a frontalchamber, indicated generally at 15,'which extends axially to the firstof the group of discs 38-463 having solid central webs. The journalmember 48, carried by the inner web portion of the member 31 whichdefines the aperture 31a, includes a forwardly extending axial portion16 which is rotatable in suitable ball bearings forming parts of thethrust bearing assembly 21 already mentioned. The bearing assembly 21further comprises a tubular bracket or housing 11 having an annularflange 18 which is bolted or otherwise secured to an inwardly cantedflange 1S of the engine core structure I2.

Formed interiorly of the housing 11 and flange 19 is a chamber 80,within which a lubricant pump 8| or other auxiliary device may bemounted, and operatively connected to a toothed portion. 52 of thejournal member 48 through the medium of a gear 83. It will be noted thatwith the apparatus constructed and arranged as shown in Fig. 2, thethrust bearing assembly 21 is substantially contained within the axialchamber 15 formed in the rotor of the compressor I8, so that the span ofthe spindle aggregate between the two bearings 21 and 3B is less thanthe overall length thereof. This construction, making practicable asubstantial decrease in the length of the span and load deflection ofthe spindle aggregate between bearings, will in effect raise thecritical speed of the power plant, and preserve better compressor sealclearances, particularly near the last stages.

From the foregoing description of a typical gas turbine power plantconstructed in accordance with the invention, it will now be apparentthat the improved spindle aggregate, comprising the compressor rotor,large diameter hollow shaft and turbine rotor in the order named, iswell adapted for support on fore and aft bearings without therequirement of a conventional intermediate bearing, thereby dispensingwith elements and structure which would otherwise add weight. to theapparatus. By mounting the described spindle aggregate on a pair ofbearings so spaced that tbe span between the bearings is less than theover-all length of the spindle aggregate, the deflection of the spindleaggregate, under gyrosccpic and gravitational loading incident to highspeed operation, will be reduced to a minimum, thus rendering feasiblethe use of eiciently small clearances between the rotary and stationaryblades of the machine. In addition, the provision of the central chamberin the compressor rotor for receiving the adjacent bearing facilitatesconstruction of an engine of desirable dimensions without sacrifice inpower or thrust rating.

What is claimed is:

l.. In elastic iiuid rotary apparatus including casing structure, a pairof spaced bearings supported in said casing structure, and a spindleaggregate mounted substantially between and journaled on said bearings,said spindle ag'- gregate including a rotor assembly having a pluralityof annular members carrying radially extending blades and joined incoaxial relation, the annular members adjacent one end of said spindleaggregate having central openings forming an axially disposed chamberreceiving one of said bearings, a tubular bracket secured to said casingstructure outwardly of said rotor assembly and projecting into saidchamber holdthe last-mentioned bearing therein,A and a spindle memberrotatably mounted in the latter bearing and secured to the innermost ofsaid annular members having central openings, whereby said rotorassembly is constructcd and arranged to overhang said last-mentionedbearing to limit the necessary spacing thereof from the other bearing toa distance less than the full length of the spindle aggregate.

2. In a gas turbine power plant including cylindrical casing structurehaving a fluid inlet end and a fluid discharge end, a spindle aggregaterotat-ably mounted longitudinally within said casing structure andcomprising a compressor rotor disposed near said inlet end and a turbinerotor disposed near said outlet end, a pair of spaced bearing assembliesconstituting the sole support of said spindle aggregate in said casingstructure, one of said bearing assemblies being mounted adjacent thedownstream side of said turbine rotor, said compressor rotor comprisinga number of abutting annular members having central openings forming anaxially disposed chamber open at the upstream side thereof, a journalmember secured to one of said apertured members withinn said chamber,and a bracket mounted in said casing structure supporting the other ofsaid two bearing assemblies within said chamber and in cooperativerelation with said journal member, whereby said spindle aggreg-ate isconstructed and arranged to overhang the lastmentionedbearing assemblyfor minimizing the span between points of support for said spindleaggregate.

3. In elastic fluid rotary apparatus including casing structure, -a pairof spaced bearings supported in said casing structure, and a spindleaggregate mounted substantially between and journaled on said bearings,said spindle aggregate including a rotor assembly having a plurality ofannularmembers carrying radially extending blades and joined in coaxialrelation, the annular members adjacent one end of said rotor assemblyhaving central openings forming an axially disposed chamber receivingone of said bearings, a tubul-ar bracket secured to said casingstructure outwardly of said rotor assembly and projecting into saidchamber holding the last-mentioned bearing therein, and a lubricant pumpmounted at least partially within said chamber and operatively connectedto said rotor assembly.

4. In a gas turbine power plant including cylindrical casing structurehaving a fluid inlet end and a fluid discharge end, a spindle aggregaterotatably mounted longitudinally Within said casing structure andcomprising a compressor rotor disposed near said inlet end and a turbinerotor disposed near said outlet end, a pair of spaced bearing assembliesconstituting the sole support of said spindle aggregate in s-aid casingstructure, one of said bearing assemblies being mounted adjacent thedownstream side of said turbine rotor, said compressor rotor comprisinga plurality of interlocked annular members and longitudinally disposedstuds securing said members together at points radially spaced from thecommon axis thereof, a number of adjacent annular members having centralapertures forming a chamber open at the end of said compressor rotor, abracket mounted in said casing structure and projecting into saidchamber supporting the other of said bearing assemblies, and a journalmember disposed within said chamber and secured radially inwardly ofsaid studs t-o one of said apertured annular members, said journalmember being rotatably mounted in the lastmentioned bearing, the span ofsaid spindle ag gregate between said tWo bearings being less than theoverall length thereof for minimizing deection under gyroscopic andgravitational loading.

5. The combination of claim 4 further dened in that the interlockedannular members having teeth projecting axially of said annular membersto prevent relative turning between the annular members during operationand that the longitudinally disposed studs securely hold the teeth ofnext adjacent annular members in engagement against axial displacement.

6. The combination of claim 4, and the confronting ends of thecompressor .rotor and turbine rotor being sustained solely by abearingless hollow shaft rigidly secured to the said ends of the rotors.

JOSEF A. RYDMARK. HAAKON O. PEDERSEN.

REFEIENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PA'I'ENTs Date

